Filament support for series lamps



March 8, 1927, 1,629,487

A. LPOWELL FILAMENT SUPPORT FOR SERIES LAMPS Filed Dec. 19, 1921 F165-F566- F's INVENTOR ARTHUR 1 POWELL.

ATTORNEY ARTHUR LESTER POWELL, 0F BLOOIVLFIELD, NEW JERSEY, ASSIGNOR TOHOUSELAIVIP COMPANY, A CORPORATION OF PENNSYLVANIA.

WESTING- FILAMENT SUPPORT FOR SERIES LAMPS.

Application filed December 19, 1921. Serial No. 523,262.

This invention relates to improvements in electric incandescent lampsand relates more particularly to lamps employed in series systems.

An object of the invention is to provide a resilient support for thefilament of a lamp by shaping the leading-in wires thereof so they wellreadily yield with the expansion and construction of the filament.

Although my invention may be generally practiced in connection withlamps of a variety of types, it has been found exceedingly advantageouswhen associated with a lamp in which a coil filament, having its axialline coincident with the axial line of the bulb, is employed. Lamps ofthis type are commonly used in series systems and are known as streetseries lamps.

In lamps of the character described above, i. e., where the filament isdisposed in a vertical position, considerable breakage of thefilamenthas heretofore occurred. This breakage is mainly attributable to therigid ity of the supports employed in such lamps. Those supports, beingunyielding, opposed the vertical movement of the filament during itsalteration in length from-temperature changes. I

The temperature under which a lamp 0perates necessitates the provisionof means for permitting the free expansion and contraction of thefilament. Since the rate of cooling is proportional to the difference intemperature between the cooling body and its environment. it willreadily be seen that the filament which operates at a much highertemperature than the leads will cool with greater rapidity than theleads, thus exerting a tensional and compressive force in the filament,when leads of the usual rigidity are employed.

Obviously, when the filament is secured to supports of the usualimmobility, its movement is opposed and the compressive and tensionalforces are confined within the filament, with detrimental resultsgenerally causing a break in the filament wire at a point adjacent theleading-in wires.

The present invention provides supports which will readily yield withthe expansion and contraction of the filament. and thercbv materiallydecrease the detrimental effects of v the unequal expansion andcontraction. The increased resiliency of the support wires is alsoadvantageous when shipping lamps, inasmuch as the greater part of theshocks will be absorbed or dissipated and Fig. 3 is a plan view of Fig.1;

Fig. 4 illustrates a modification in which the resiliencyof thesupporting wires is in creased by a formation different than that shownin Fig. 1; i I

Fig. 5 is a view showing the support wires having a double bend;

Fig. 6 is a view showing the resiliency obtained by a; looped formationof the leadingin wires; and,

Fig. 7 shows a portion of the leading-inf wires in the form of a helicalspring.

In the present embodiment of the invention, a simple and efficient meansof attaining the desirable increase in resiliency of the supports ofleading-in wires is attained by providing the supports-with a bendintermediate their ends and the press of the lamp. This formation of thesupports increases their resiliency as a holder for a filament. Thesupporting wires may be made to conform to a variety of shapes whichwill serve to accomplish the desired ends.

Referring now to the drawing and particularly to Fig. 1, it will'bereadily seen that, in its structural details, the lamp illustratedconforms to the well-known type of street series incandescent lamp. Sucha lamp may consist of a bulb 7 in which a concentrated metallic filament8, which is preferably of helical shape, is positioned substantially onthe vertical axis 9 ofthe lamp. The filament may be supported by havingits cured to a pair of leadingin wires 11 and 12; respectively. Theleading-in wires extend through a press 13 of a tubular stem 14 which issealed to the bulb 7 within a ter- 105 upper and lower ends welded orotherwise sestantially in the same vertical plane. It has,

however, been found desirable to offset the upper portion 19 of the,leading-in wire 11 with respect to the said plane in order to minimizethe amount of wire positioned in front of the light source, thus greatlyreducing the shadow. The upper ends 21 and 22 of the leading-in wires 11and 12, respectively, are bent substantially at right angles to eachother and to the axial line 9 of the bulb, and the ends of the filament8 are welded or otherwise attached thereto.

Itis evident that, by supporting the filament as illustrated, a moreelastic and otherwise resilient mount is obtained for the filament,inasmuch as the upper and lower por tions, on opposite sides of therespective bends of the support wires, provide members or lever armsfulcrumed at the bends 16. Because of this leverage, a resilient supportfor the filament is provided and thus the filament is permitted toexpand or contract without detrimental opposition.

Although the present invention provides the desirable resiliency of thesupports to' accommodate the vertical movement of the filament, it alsomaintains the necessary resiliency for the lateral movement of thesupports to prevent rupture thereof by reason of shocks or jars duringtransportation or other vibration of the lamp.

It will also be appreciated that the support wires have asubstantially-equal degree of resiliency and when the filament expandsor contacts, the support Wires yield an equal amount, thus the filamentmaintains its relative position with respect to the globe.

It will be readily understood that the support or leading-in wires maybe shaped in a variety of ways to afford the resiliency produced by theconstruction illustrated in Fig. 1. In Fig. 4, a triple bend is providedto render the supports resilient, while, in

aeaaaar Fig. 5, the desired resiliency is obtained by means of a reversebend 23. In Fig. 6, a loop 24 of nodal shape is provided and in Fig. 7,the wire is made to conform to a helical spring 35. These variousconstructions tend to increase the resiliency of the support and thusdecrease the breakage of the filament.

It is obvious that many modifications and structural variations may beresorted to utilizing this invention and it is understood that theinvention contemplates all such modifi cations as come within the scopeof the appended claims.

'What is claimed is:

1. An incandescent electric lamp having leading-in wires, a coiledfilament, said leading-in wires being bent to angular form to providerelatively long lever members, portions at the free ends of said membersbeing positioned atv right angles to each other and in spaced relationand having said filament secured to said ends.

2. An incandescent electric lamp having leading-in wires, a coiledfilament, leadingin conductors associated with said lamp and havingtheir free ends secured to the opposite ends of said filament to-supportthe same with its axis coincident to the longitudinal axis of the lamp,said leading-in wires being provided with bendsto increase theirresiliency as supports, portions of the ends of said wires beingpositioned trans verse to the axial line of said lamp and at rightangles to each other.

3. An incandescent electric lamp having leading-in wires supporting acoiled filament substantially coincident with the longitudinal axis ofsaid lamp, said leading-in wires being bent to angular form to providerelatively long lever members, portions at the free ends of said membersbeing positioned at right angles to each other and in spaced relationand having said filament secured to said ends.

In testimony whcrcof, I have hereunto subscribed my name this 17th dayof December, 1921.

ARTHUR LESTER IOlVlGLL.

